package BC72_平均身高;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        float sum = 0;
        for (int i = 0; i < 5; i++){
            sum += sc.nextFloat();
        }
        System.out.printf("%.2f", sum / 5.0);
    }
}
